The invention relates to a gun in which the gun barrel is seated to be displaced in a cradle barrel.
A gun of this type is known from, for example, German Laid open Patent Application DE 31 48 265 A1. Here, the barrel is seated in two slide-bushing bearings that are disposed at the muzzle and breech ends of the cradle barrel. A drawback of this known slide-bushing mounting is that the gun barrel, for example of a tank gun, must rest on the lower inside edge of the bearing because of its mass, and rises because of the barrel expansion that occurs upon firing. This causes the barrel to vibrate, and adversely affects the jump error of the respective projectile.
It is known from German Laid open Patent Application DE 39 36 454 A1 to avoid the barrel vibrations that occur upon firing by using bearings that are free of the lift effect, instead of conventional slide-bushing bearings. With bearings free of the lift effect, the gun barrel does not impact a fixed stop in the radial direction upon firing, so the barrel can expand horizontally as well as vertically. Four guide rails, which are uniformly distributed around the circumference of the barrel and extend in the direction of the longitudinal axis, serve in mounting the gun barrel in the cradle. The guide rails are formed as slide rails, and extend into corresponding guide grooves of the cradle barrel such that the directions of the bearing force and the radial barrel expansion are perpendicular to one another.
The biggest drawback of this mounting arrangement is that the guide rails and guide grooves extend past both bearing points, which is complex from a manufacturing engineering standpoint. Furthermore, changing the barrel in such guns is complicated and therefore time-consuming.
Finally, German Patent Application No. 102 26 534.8, corresponding to U.S. patent application Ser. No. 10/414,242, filed Apr. 16, 2003, discloses a gun in which the lifting effect of the barrel is extensively avoided through the provision of a slide-bushing bearing, at least on the muzzle side of the gun barrel, but preferably also at the rear of the barrel. The slide-bushing bearing comprises a barrel bush busing in which the gun barrel is seated, free from the lift effect. The outside surface of the bushing is seated in the cradle barrel so as to slide in a form-fit (i.e., with the smallest amount of play), effecting an axial and radial sliding guidance of the gun barrel that are independent of one another. Upon firing, tab-shaped projections engage corresponding groove-shaped recesses in the barrel bush, effecting the radial sliding guidance of the gun barrel by holding it centrally in the barrel bushing. A radial expansion is, again, compensated by a predetermined amount of play between the inside or inner surface of the barrel bush and the gun barrel, or an inner ring that is attached to it, fixed against relative rotation, and supports the tab-shaped projections.
One of the disadvantages of this gun barrel is the relatively complicated arrangement of the tab-shaped projections, which must be mounted either directly to the barrel or indirectly via an intermediate ring.